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1.
Chemosphere ; : 126825, 2020 Apr 21.
Artigo em Inglês | MEDLINE | ID: mdl-32381281

RESUMO

Neuroactive compounds are routinely detected in surface waters at concentrations that pose potential threats to wildlife. Exposure to neurotoxicants can adversely affect exposed organism by altering ecologically-important behaviors (e.g., feeding and predator response) that are likely to have important repercussions for populations. These compounds can elicit behavioral effects at concentrations lower than those that induce overt toxicity as indicated by mortality or decreased growth. Though a wide variety of methods have been employed to assess the behavior of early life stage fish, it is unclear which assays are best suited for identifying ecologically-relevant behavioral changes following exposures to neurotoxicants. The goal of the present study was to promote the use of behavioral assays for assessing the behavioral impacts of exposure to neurotoxic compounds by comparing the performance of different behavioral assays in larval fish. To achieve this goal, the sensitivity and practicality of three behavioral assays (i.e., feeding, optomotor response, and C-start assays) were compared in larval fathead minnows exposed to a known neurotoxicant, chlorpyrifos. There were significant alterations in the performance of fathead minnow larvae in all three behavioral assays in response to a 12-d embryo-larval exposure to chlorpyrifos. However, feeding and C-start were the most practical of the selected assays, as they took less time and allowed for larger samples sizes. Further work to standardize behavioral testing methods, and to link alterations to ecologically-relevant behaviors, will help promote the use of these assays when investigating the potential environmental impacts of neurotoxic compounds.

2.
Artigo em Inglês | MEDLINE | ID: mdl-32439514

RESUMO

Recent studies have utilized the fathead minnow (Pimephales promelas) to explore the immunotoxic effects associated with a variety of environmental contaminants in the absence of immunological stimuli. Though this approach allows for alterations in the resting immune system to be detected, previous evidence suggests that many immunotoxic effects may only manifest in the activated immune system. However, basic immune responses to pathogens have not been well described in this species. To expand the utility of the fathead minnow as a model for immunotoxicity testing, a more comprehensive understanding of the activated immune system is required. As such, the main goal of this study was to characterize the transcriptomic response to pathogen infection in the fathead minnow using RNA sequencing. To achieve this goal, female fathead minnows were intraperitoneally injected with either Hank's Balanced Salt Solution (sham-injected) or Yersinia ruckeri (pathogen-injected). Eight hours following injection, fish were sacrificed for the assessment of general morphological (i.e., mass, length, condition factor, hepatic index) and immunological (i.e., leukocyte counts, spleen index) endpoints. To assess the molecular immune response to Y. ruckeri, kidney tissue was collected for transcriptomic analysis. A comparison of sham- and pathogen-injected fish revealed that >1800 genes and >500 gene networks were differentially expressed with pathogen challenge. Gene networks associated with inflammation, innate immunity, complement, hemorrhaging and iron absorption are highlighted and their utility within the context of immunotoxicity is discussed. These data reveal pathogen-related molecular endpoints to improve data interpretation of future studies utilizing the fathead minnow as a model for immunotoxicity.

3.
Environ Toxicol Chem ; 37(10): 2530-2541, 2018 10.
Artigo em Inglês | MEDLINE | ID: mdl-29920761

RESUMO

The fathead minnow fish embryo toxicity (FET) test has been proposed as a more humane alternative to current toxicity testing methods as younger organisms are thought to experience less distress during toxicant exposure. However, the FET test protocol does not include endpoints that allow for the prediction of sublethal adverse outcomes, limiting its utility relative to other test types. Researchers have proposed the development of sublethal endpoints for the FET test to increase its utility. The present study 1) developed methods for previously unmeasured sublethal metrics in fathead minnows (i.e., spontaneous contraction frequency and heart rate) and 2) investigated the responsiveness of several sublethal endpoints related to growth (wet wt, length, and growth-related gene expression), neurodevelopment (spontaneous contraction frequency, eye size, and neurodevelopmental gene expression), and cardiovascular function and development (pericardial area, heart rate, and cardiovascular system-related gene expression) as additional FET test metrics using the model toxicant 3,4-dichloroaniline. Of the growth, neurological, and cardiovascular endpoints measured, length, eye size, and pericardial area were found to be more responsive than the other endpoints evaluated. Future studies linking alterations in these endpoints to longer-term adverse impacts are needed to fully evaluate the predictive power of these metrics in chemical and whole-effluent toxicity testing. Environ Toxicol Chem 2018;37:2530-2541. © 2018 SETAC.


Assuntos
Sistema Cardiovascular/embriologia , Cyprinidae/embriologia , Embrião não Mamífero/metabolismo , Determinação de Ponto Final , Sistema Nervoso/embriologia , Testes de Toxicidade , Animais , Peso Corporal , Cyprinidae/anatomia & histologia , Cyprinidae/genética , Cyprinidae/fisiologia , Embrião não Mamífero/efeitos dos fármacos , Olho/anatomia & histologia , Fertilização , Proteínas de Peixes/genética , Proteínas de Peixes/metabolismo , Regulação da Expressão Gênica no Desenvolvimento , Frequência Cardíaca
4.
Fish Shellfish Immunol ; 80: 80-87, 2018 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-29859315

RESUMO

Exposures to polybrominated diphenyl ethers (PBDEs) have been shown to alter immune function in adult organisms across a variety of taxa. However, few if any studies have investigated the long-term consequences of early life stage PBDE exposures on immune function in fish. This study sought to determine the effects of early life stage BDE-47 exposure on pathogen resistance in the fathead minnow (Pimephales promelas) following an extended depuration period (≥180 d). Minnows were exposed to BDE-47 via a combination of maternal transfer and diet through 34 days post fertilization (dpf), raised to adulthood (>215 dpf) on a clean diet, then subjected to pathogen resistance trials. Early life stage exposures to BDE-47 did not affect the ability of females to survive from Yersinia ruckeri infection. However, the survival of BDE-47 exposed males was significantly reduced relative to controls, indicating that developmental exposures to BDE-47 altered male immunity. Because BDE-47 is a known thyroid hormone disruptor and thyroid hormone disruptors have the potential to adversely impact immune development and function, metrics indicative of thyroid disruption were evaluated, as were immune parameters known to be altered in response to thyroid disruption. BDE-47 exposed minnows exhibited signs of thyroid disruption (i.e., reduced growth); however, no alterations were observed in immune parameters known to be influenced by thyroid hormones (i.e., thymus size, expression of genes associated with lymphoid development) suggesting that the observed alterations in immunocompetence may occur through alternative mechanisms. Regardless of the mechanisms responsible, the results of this study demonstrate the potential for early life stage PBDE exposures to adversely impact immunity and illustrate that the immunological consequences of PBDE exposures are sex dependent.


Assuntos
Cyprinidae/imunologia , Resistência à Doença/efeitos dos fármacos , Disruptores Endócrinos/toxicidade , Retardadores de Chama/toxicidade , Éteres Difenil Halogenados/toxicidade , Animais , Cyprinidae/genética , Embrião não Mamífero , Feminino , Regulação da Expressão Gênica/efeitos dos fármacos , Larva , Masculino , Caracteres Sexuais , Timo , Glândula Tireoide , Yersiniose/imunologia , Yersiniose/veterinária , Yersinia ruckeri
5.
Ecotoxicol Environ Saf ; 153: 45-53, 2018 May 30.
Artigo em Inglês | MEDLINE | ID: mdl-29407737

RESUMO

The fathead minnow fish embryo toxicity (FET) test has been identified as a potential alternative to toxicity test methods that utilize older fish. However, several challenges have been identified with the fathead minnow FET test, including: 1) difficulties in obtaining appropriately-staged embryos for FET test initiation, 2) a paucity of data comparing fathead minnow FET test performance to the fathead minnow larval growth and survival (LGS) test and 3) a lack of sublethal endpoints that could be used to estimate chronic toxicity and/or predict adverse effects. These challenges were addressed through three study objectives. The first objective was to optimize embryo production by assessing the effect of breeding group composition (number of males and females) on egg production. Results showed that groups containing one male and four females produced the largest clutches, enhancing the likelihood of procuring sufficient numbers of embryos for FET test initiation. The second study objective was to compare the performance of the FET test to that of the fathead minnow LGS test using three reference toxicants. The FET and LGS tests were similar in their ability to predict the acute toxicity of sodium chloride and ethanol, but the FET test was found to be more sensitive than the LGS test for sodium dodecyl sulfate. The last objective of the study was to evaluate the utility and practicality of several sublethal metrics (i.e., growth, developmental abnormalities and growth- and stress-related gene expression) as FET test endpoints. Developmental abnormalities, including pericardial edema and hatch success, were found to offer the most promise as additional FET test endpoints, given their responsiveness, potential for predicting adverse effects, ease of assessment and low cost of measurement.


Assuntos
Cyprinidae/crescimento & desenvolvimento , Embrião não Mamífero/efeitos dos fármacos , Reprodução/efeitos dos fármacos , Testes de Toxicidade/métodos , Poluentes Químicos da Água/toxicidade , Alternativas ao Uso de Animais , Animais , Cyprinidae/embriologia , Feminino , Larva/efeitos dos fármacos , Larva/crescimento & desenvolvimento , Sensibilidade e Especificidade
6.
Fish Shellfish Immunol ; 61: 163-172, 2017 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-28027985

RESUMO

The fathead minnow (Pimephales promelas) is an environmental sentinel species, commonly used in toxicity testing. However, there is a lack of data regarding basic immune function in this species. To improve the usefulness of the fathead minnow as a model for basic immune function and immunotoxicity, this study sought to 1) compare the differential expression of immune function genes in naïve fathead minnows and 2) determine the effects of pathogen exposure on immune gene expression and spleen index. To accomplish this, kidney, spleen and liver tissue were collected three days post injection (dpi) from adult male fathead minnows from each of the following groups: 1) uninjected control 2) sham-injected (Hank's balanced salt solution) and 3) pathogen-injected (Yersinia ruckeri). Spleen tissue was also collected at seven and 14 dpi. Differential tissue expression of immune function genes was evaluated in naïve minnows and expression patterns were similar to those found in other fish species, with liver tissue generally having the highest amount of expression. Following pathogen injection, the expression of complement component 3 (c3) (4.4-fold, kidney; 2.5-fold, liver), interleukin 11 (il11) (4.8-fold, kidney; 15.2-fold, liver) and interleukin 1ß (il1ß) (8.2-fold, kidney; 17.2-fold, spleen; 2.6-fold, liver) were significantly upregulated. Elastase 2 (elas2) was significantly downregulated (5.8-fold) in liver tissue. A significant increase in spleen index at seven dpi was also observed in pathogen-injected minnows. This study has identified endpoints that are part of the normal response to pathogen in fathead minnows, an essential step toward the development of the fathead minnow as a model for immunotoxicity evaluations.


Assuntos
Cyprinidae , Doenças dos Peixes/genética , Proteínas de Peixes/genética , Regulação da Expressão Gênica , Imunidade Inata , Yersiniose/veterinária , Animais , Doenças dos Peixes/imunologia , Doenças dos Peixes/microbiologia , Proteínas de Peixes/metabolismo , Masculino , Especificidade de Órgãos , Distribuição Aleatória , Yersiniose/genética , Yersiniose/imunologia , Yersiniose/microbiologia , Yersinia ruckeri/fisiologia
7.
Environ Toxicol Pharmacol ; 48: 237-244, 2016 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-27838513

RESUMO

Few studies have investigated the thyroid-disrupting effects of polybrominated diphenyl ethers (PBDEs) across multiple levels of biological organization in anurans, despite their suitability for the screening of thyroid disruptors. Therefore, the present study evaluated the effects of 2,2',4,4'-tetrabromodiphenyl ether (BDE-47) on development, thyroid histology and thyroid hormone-related gene expression in Xenopus laevis exposed to 0 (control), 50 (low), 500 (medium) or 5000µg BDE-47/g food (high) for 21days. Only the high dose of BDE-47 hindered growth and development; however, thyroid hormone-associated gene expression was downregulated in the brains of tadpoles regardless of dose. These results show that BDE-47 disrupts thyroid hormone signaling at the molecular and whole-organism levels and suggest that gene expression in the brain is a more sensitive endpoint than metamorphosis. Furthermore, the altered gene expression patterns among BDE-47-exposed tadpoles provide insight into the mechanisms of PBDE-induced thyroid disruption and highlight the potential for PBDEs to act as neurodevelopmental toxicants.


Assuntos
Disruptores Endócrinos/toxicidade , Expressão Gênica/efeitos dos fármacos , Éteres Difenil Halogenados/toxicidade , Larva/efeitos dos fármacos , Glândula Tireoide/efeitos dos fármacos , Hormônios Tireóideos/genética , Administração Oral , Animais , Peso Corporal/efeitos dos fármacos , Relação Dose-Resposta a Droga , Larva/genética , Larva/crescimento & desenvolvimento , Larva/metabolismo , Receptores dos Hormônios Tireóideos/genética , Glândula Tireoide/metabolismo , Glândula Tireoide/patologia , Xenopus laevis
8.
PLoS One ; 11(11): e0167068, 2016.
Artigo em Inglês | MEDLINE | ID: mdl-27875572

RESUMO

Acinetobacter baumannii is an opportunistic Gram-negative pathogen that causes a wide range of infections including pneumonia, septicemia, necrotizing fasciitis and severe wound and urinary tract infections. Analysis of A. baumannii representative strains grown in Chelex 100-treated medium for hemolytic activity demonstrated that this pathogen is increasingly hemolytic to sheep, human and horse erythrocytes, which interestingly contain increasing amounts of phosphatidylcholine in their membranes. Bioinformatic, genetic and functional analyses of 19 A. baumannii isolates showed that the genomes of each strain contained two phosphatidylcholine-specific phospholipase C (PC-PLC) genes, which were named plc1 and plc2. Accordingly, all of these strains were significantly hemolytic to horse erythrocytes and their culture supernatants tested positive for PC-PLC activity. Further analyses showed that the transcriptional expression of plc1 and plc2 and the production of phospholipase and thus hemolytic activity increased when bacteria were cultured under iron-chelation as compared to iron-rich conditions. Testing of the A. baumannii ATCC 19606T plc1::aph-FRT and plc2::aph isogenic insertion derivatives showed that these mutants had a significantly reduced PC-PLC activity as compared to the parental strain, while testing of plc1::ermAM/plc2::aph demonstrated that this double PC-PLC isogenic mutant expressed significantly reduced cytolytic and hemolytic activity. Interestingly, only plc1 was shown to contribute significantly to A. baumannii virulence using the Galleria mellonella infection model. Taken together, our data demonstrate that both PLC1 and PLC2, which have diverged from a common ancestor, play a concerted role in hemolytic and cytolytic activities; although PLC1 seems to play a more critical role in the virulence of A. baumannii when tested in an invertebrate model. These activities would provide access to intracellular iron stores this pathogen could use during growth in the infected host.


Assuntos
Infecções por Acinetobacter/enzimologia , Acinetobacter baumannii/enzimologia , Acinetobacter baumannii/patogenicidade , Proteínas de Bactérias/metabolismo , Genoma Bacteriano , Fosfolipases Tipo C/metabolismo , Células A549 , Infecções por Acinetobacter/genética , Acinetobacter baumannii/genética , Animais , Proteínas de Bactérias/genética , Bovinos , Modelos Animais de Doenças , Cavalos , Humanos , Ovinos , Fosfolipases Tipo C/genética
9.
Environ Sci Technol ; 50(14): 7834-41, 2016 07 19.
Artigo em Inglês | MEDLINE | ID: mdl-27326452

RESUMO

2,2',4,4'-Tetrabromodiphenyl ether (BDE-47), a compound manufactured for use as a flame retardant, is a ubiquitous environmental contaminant and suspected endocrine disruptor. Though several studies have explored the reproductive effects of BDE-47 in adult fish, there is a paucity of data regarding the reproductive effects of early life stage exposure. The goal of this study was to assess the reproductive effects of early life stage BDE-47 exposure in fathead minnows (Pimephales promelas). To achieve this, minnows were exposed to either a low (57.68 µg BDE-47/g Artemia) or high (392.59 µg BDE-47/g Artemia) dose of BDE-47 from fertilization to 34 days postfertilization (dpf) via a combination of maternal transfer and dietary exposure. Larvae were then raised on a clean diet until sexual maturity (∼184 dpf) when reproductive function was evaluated using a 21 day breeding study. Fish exposed to BDE-47 had significantly reduced clutch size and fecundity relative to controls. BDE-47 exposed groups also had female-biased sex ratios and exposed males had fewer tubercles. Overall, this study demonstrates that exposure to BDE-47 during early life stages can alter both sexual differentiation and reproductive function.


Assuntos
Cyprinidae , Diferenciação Sexual , Animais , Disruptores Endócrinos/farmacologia , Retardadores de Chama , Reprodução/efeitos dos fármacos , Poluentes Químicos da Água/farmacologia
10.
Environ Toxicol Chem ; 35(8): 2048-57, 2016 08.
Artigo em Inglês | MEDLINE | ID: mdl-26749031

RESUMO

The goal of the present study was to evaluate the reproductive function of fathead minnows (Pimephales promelas) exposed to brominated diphenyl ether-47 (BDE-47) at doses lower than those used in previous studies. This was accomplished by evaluating the impacts of BDE-47 exposures across multiple levels of biological organization. Breeding pairs were exposed to BDE-47 via diet for 21 d, during which reproductive success was monitored. At the conclusion of the exposure, fish were euthanized to assess the effects of BDE-47 on sex steroid-related and thyroid-related transcripts, plasma androgen levels, gonadosomatic index (GSI), and secondary sexual characteristics. Several alterations in gene expression were noted including a >2.1-fold decrease in hepatic estrogen receptor α (erα) and a 2.9-fold decrease in ovarian aromatase (arom). In addition, BDE-47-exposed males experienced increases in deiodinase 2 (dio2) expression in brain tissue (∼1.5-fold) and decreases in hepatic transthyretin (ttr) expression (∼1.4-fold). Together, these gene expression alterations suggest the potential for BDE-47 to disrupt endocrine signaling. There were no significant differences in plasma hormone levels, GSI, secondary sexual characteristics, or reproductive success. Overall, the present study demonstrates that exposure to BDE-47 is capable of altering both sex steroid-related and thyroid-related transcripts but that these observed alterations do not necessarily manifest themselves at higher levels of biological organization for the endpoints selected. Environ Toxicol Chem 2016;35:2048-2057. © 2016 SETAC.


Assuntos
Cyprinidae/metabolismo , Disruptores Endócrinos/toxicidade , Monitoramento Ambiental/métodos , Éteres Difenil Halogenados/toxicidade , Reprodução/efeitos dos fármacos , Ração Animal , Animais , Encéfalo/efeitos dos fármacos , Encéfalo/metabolismo , Cruzamento , Cyprinidae/sangue , Cyprinidae/genética , Relação Dose-Resposta a Droga , Feminino , Expressão Gênica/efeitos dos fármacos , Hormônios Esteroides Gonadais/metabolismo , Fígado/efeitos dos fármacos , Fígado/metabolismo , Masculino , Hormônios Tireóideos/genética , Hormônios Tireóideos/metabolismo
11.
BMC Biotechnol ; 14: 94, 2014 Nov 14.
Artigo em Inglês | MEDLINE | ID: mdl-25394494

RESUMO

BACKGROUND: This study compared the performance of five commercially available kits in extracting total RNA from small eukaryotic tissue samples (<15 mg). Total RNA was isolated from fathead minnow (Pimephales promelas) tissues (spleen, blood, kidney, embryo, and larvae) using the Qiagen RNeasy® Plus Mini, Qiagen RNeasy® Plus Universal, Promega Maxwell® 16 LEV simplyRNA, Ambion MagMAX™-96 and Promega SimplyRNA HT kits. Kit performance was evaluated via measures of RNA quantity (e.g., total RNA amount) and quality (e.g., ratio of absorbance at 260 and 280 nm, RNA integrity number (RIN), presence of gDNA). RESULTS: With the exception of embryos, each kit generally extracted ≥5 µg of total RNA from each sample. With regard to RNA quality, the RINs of RNA samples isolated via the Plus Mini and Maxwell® 16 kits were consistently higher than those of samples extracted via the remaining three kits and for all tissues, these kits produced intact RNA with average RIN values ≥7. The Plus Universal and SimplyRNA HT kits produced moderately degraded (RIN values <7, but ≥5), while the RNA recovered via the MagMAX™ kit tended to exhibit a high degree of degradation (RIN values <5). CONCLUSIONS: Each kit was generally capable of extracting the amount of RNA required for most downstream gene expression applications suggesting that RNA yield is unlikely to be a limiting factor for any of the kits evaluated. However, differences in the quality of RNA extracted via each of the kits indicate that these kits may differ in their ability to yield RNA acceptable for some applications. Overall, the findings of this study demonstrate that there are practical differences between commercially available RNA extraction kits that should be taken into account when selecting extraction methods to be used for isolating RNA designated for gene expression analysis.


Assuntos
Estruturas Animais/química , Cyprinidae/genética , Técnicas Genéticas/instrumentação , RNA/isolamento & purificação , Animais , Automação , Cyprinidae/embriologia , Masculino , Reação em Cadeia da Polimerase , RNA/genética , Kit de Reagentes para Diagnóstico
12.
Environ Sci Technol ; 47(10): 5450-8, 2013 May 21.
Artigo em Inglês | MEDLINE | ID: mdl-23600964

RESUMO

Phototoxicity occurs when exposure to ultraviolet radiation increases the toxicity of certain contaminants, including polycyclic aromatic hydrocarbons (PAHs). This study aimed to (1) develop a quantitative model to predict the risk of PAH phototoxicity to fish, (2) assess the predictive value of the model, and (3) estimate the risk of PAH phototoxicity to larval and young of year Pacific herring (Clupea pallasi) following the Exxon Valdez oil spill (EVOS) in Prince William Sound, Alaska. The model, in which median lethal times (LT50 values) are estimated from whole-body phototoxic PAH concentrations and ultraviolet A (UVA) exposure, was constructed from previously reported PAH phototoxicity data. The predictive value of this model was confirmed by the overlap of model-predicted and experimentally derived LT50 values. The model, along with UVA characterization data, was used to generate estimates for depths of de minimiz risk for PAH phototoxicity in young herring in 2003/2004 and immediately following the 1989 EVOS, assuming average and worst case conditions. Depths of de minimiz risk were estimated to be between 0 and 2 m deep when worst case UVA and PAH conditions were considered. A post hoc assessment determined that <1% of the young herring population would have been present at depths associated with significant risk of PAH phototoxicity in 2003/2004 and 1989.


Assuntos
Peixes , Luz , Modelos Teóricos , Poluição por Petróleo , Hidrocarbonetos Policíclicos Aromáticos/toxicidade , Medição de Risco , Alaska , Animais
13.
Environ Sci Technol ; 46(3): 1877-85, 2012 Feb 07.
Artigo em Inglês | MEDLINE | ID: mdl-22165990

RESUMO

This study aimed to evaluate the utility of microarrays as a biomonitoring tool in field studies. A 15,000-oligonucleotide microarray was used to measure the hepatic gene expression of fathead minnows (Pimephales promelas) caged in four Nebraska, USA watersheds - the Niobrara and Dismal Rivers (low-impact agricultural sites) and the Platte and Elkhorn Rivers (high-impact agricultural sites). Gene expression profiles were site specific and fish from the low- and high-impact sites aggregated into distinct groups. Over 1500 genes were differentially regulated between fish from the low- and high-impact sites. Many gene expression differences (1218) were also noted when the Platte and Elkhorn minnows were compared to one another and Platte fish experienced a higher degree of transcript alterations than Elkhorn fish. These findings indicate that there are differences between the low-impact and high-impact sites, as well as between the two high-impact sites. Historical water quality data support these results as only trace levels of agrichemicals have been detected at the low-impact sites, while substantial levels of agrichemicals have been reported at the high-impact sites with agrichemical loads at the Platte generally exceeding those at the Elkhorn. Overall, this study demonstrates that microarrays can be utilized to discriminate sites with different contaminant loads from one another.


Assuntos
Cyprinidae/genética , Monitoramento Ambiental/métodos , Regulação da Expressão Gênica/fisiologia , Fígado/metabolismo , Análise de Sequência com Séries de Oligonucleotídeos/métodos , Poluentes Químicos da Água/análise , Agricultura , Análise de Variância , Animais , Biologia Computacional , Cyprinidae/fisiologia , Perfilação da Expressão Gênica , Regulação da Expressão Gênica/efeitos dos fármacos , Nebraska , Rios , Poluentes Químicos da Água/toxicidade
14.
Aquat Toxicol ; 105(1-2): 189-98, 2011 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-21723217

RESUMO

The goal of the current study was to determine whether sediments from agriculturally intense watersheds can act as a potential source of anti-estrogenic endocrine-disrupting compounds. The specific objectives of the current study were to determine (1) whether female fathead minnows (Pimephales promelas) experience alterations in endocrine function when exposed to sediments collected from agriculturally intense watersheds and (2) if these sediments display anti-estrogenic activity in an in vitro assay. In addition, sediment samples were analyzed for the presence of steroid hormones and pesticides associated with local agricultural practices. To accomplish this, sediments and water were collected from three sites within two agriculturally intense Nebraska watersheds (Bow Creek and the Elkhorn River). In 2009, minnows were exposed to sediment and/or water collected from the two Bow Creek sites (East Bow Creek and the Confluence) in the laboratory, while in 2010, minnows were exposed to sediment and/or water from East Bow Creek, the Confluence and the Elkhorn River. Following the 7-day exposure period, the hepatic mRNA expression of two-estrogen responsive genes, estrogen receptor α (ERα) and vitellogenin (Vtg) was determined. In 2009, females exposed to Confluence sediments, in the presence of laboratory water or Confluence water, experienced significant reductions in ERα expression relative to unexposed and Confluence water-exposed females. The defeminization of these females suggests the presence of a biologically available anti-estrogenic compound in sediments collected from this site. In 2010, sediments were assessed for anti-estrogenic activity on days 0 and 7 of the exposure period using a 4-h yeast estrogen screen. Lipophilic extracts (LEs) of day 0 sediments collected from the Confluence and the Elkhorn River induced significant reductions in the estrogenic reporter activity of treated yeast cultures suggesting the presence of a lipophilic anti-estrogenic compound in these extracts. Chemical analysis revealed the presence of a variety of steroid hormones, including those associated with the production of beef cattle (i.e. ß-trenbolone, α-zearalanol and α-zearalenol), in sediments indicating that compounds utilized by local beef cattle operations are capable of entering nearby watersheds. Overall, the results of this study indicate that an environmentally relevant anti-estrogenic compound is present in sediments from agriculturally intense watersheds and that this compound is bioavailable to fish. Furthermore, the presence of steroid hormones in sediments from these watersheds provides evidence indicating that steroids are capable of sorbing to sediments.


Assuntos
Monitoramento Ambiental/métodos , Moduladores de Receptor Estrogênico/toxicidade , Sedimentos Geológicos/química , Poluentes Químicos da Água/toxicidade , Agricultura/estatística & dados numéricos , Animais , Cyprinidae/metabolismo , Disruptores Endócrinos/toxicidade , Receptor alfa de Estrogênio/genética , Receptor alfa de Estrogênio/metabolismo , Feminino , Fígado/metabolismo , RNA Mensageiro/metabolismo , Vitelogeninas/genética , Vitelogeninas/metabolismo , Abastecimento de Água
15.
Environ Toxicol Chem ; 30(10): 2253-60, 2011 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-21732415

RESUMO

The Bow Creek watershed (Nebraska, USA) is dominated by the production of beef cattle and row crops; therefore, surface waters are likely to receive runoff containing steroid hormones and pesticides. The goal of the present study was to determine the occurrence and endocrine effects of agrichemicals in this watershed. To accomplish this, four sites within the watershed-Pearl, Bow, and East Bow Creeks and a site at the confluence with the Missouri River-were selected. In June of 2008, polar organic chemical integrative samplers (POCIS) were deployed at each site, whereas in June of 2009, water and sediment samples were collected. Caged fathead minnows (Pimephales promelas) were deployed at all of the selected sites in both years. Analysis of these samples revealed that steroid hormones were not present; however, pesticides were present in POCIS extracts and water samples. In general, the amount of pesticides was higher in POCIS retrieved from Pearl and Bow Creeks than in POCIS from East Bow Creek and the confluence. This variation between sites appeared to be related to row crop density, as row crop land cover surrounding the Pearl and Bow Creek sites was higher than that surrounding the East Bow and confluence sites. To determine the endocrine effects of agrichemicals within this watershed, the hepatic mRNA expression of vitellogenin and estrogen receptor α (ERα), as well as the gonadal expression of P450 aromatase A, was determined for the caged minnows. Females deployed at East Bow Creek and the confluence experienced decreases in the expression of ERα, suggesting that these females had been defeminized; however, this defeminization could not be attributed to any of the pesticides detected at these sites.


Assuntos
Agroquímicos/química , Cyprinidae/metabolismo , Disruptores Endócrinos/química , Monitoramento Ambiental/métodos , Poluentes Químicos da Água/química , Agroquímicos/análise , Animais , Aromatase/análise , Bovinos , Disruptores Endócrinos/análise , Receptor alfa de Estrogênio/análise , Feminino , Hormônios Esteroides Gonadais/análise , Hormônios Esteroides Gonadais/química , Fígado/metabolismo , Masculino , Nebraska , Praguicidas/análise , Praguicidas/química , Rios/química , Vitelogeninas/análise , Poluentes Químicos da Água/análise
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